Question

AIDS can be detected by RT-PCR at an early stage as

• A. it detects the antibodies produced against the virus
• B. it amplifies even a single copy of RNA to produce millions of copies of cDNA
• C. it avoids contamination of samples with other DNA
• D. all of these

Answer 1

The correct option is B it amplifies even a single copy of RNA to produce millions of copies of cDNA

RT-PCR is a highly sensitive technique which is used for detection and quantification of RNA. PCR does not work on RNA directly. Hence in RT-PCR, the RNA is reverse transcribed into complementary DNA (cDNA), using reverse transcriptase, and then PCR is used to amplify the cDNA (also known as copy DNA).

AIDS is caused by HIV, which is a retrovirus (viruses containing RNA as genetic material). RT-PCR is used for detection of HIV as it amplifies even a single copy of RNA to produce millions of copies of cDNA. Thus the presence of even a tiny number of viruses can give a positive result, thereby allowing its early detection.

RT-PCR is carried out as follows:

Antibodies are produced in the body when any foreign agent (pathogen) enters the body to fight against it. RT-PCR does not detect antibodies.

RT-PCR, as a process, does not target at preventing the contamination of the sample. For that the sample has to be kept in sterile tubes and maintained at low temperature to avoid any enzymatic activity or degradation.